Heterogeneous catalysts have many advantages over their homogeneous counterparts including recyclability, easier separation from product streams and, often, greater stability. Accordingly, nearly 80% of industrial processes employ heterogeneous catalysts (Synthesis of Solid Catalysts; de Jong, K. P., Ed.; Wiley-VCH: Germany, 2009). Despite their broad implementation, the design and synthesis of new highly active and selective heterogeneous catalysts remains an important goal. Typically, heterogeneous catalysts are supported on complex materials in which it is difficult to characterize active sites and establish structure-activity relationships in order to rationally design improved catalytic species (Boudart, M.; Djéga-Mariadassou, G. Kinetics of Heterogeneous Catalytic Reactions; Princeton University Press: Princeton, N.J., 1984; Thomas, J. M.; Thomas, W. J. Principles and Practice of Heterogeneous Catalysis; VCH: New York, 1997). Thus, there is still a need for methods to synthesize heterogeneous catalysts in a controlled and well-defined manner and for their computational characterization.
One approach to access well-defined “single-site” heterogeneous catalysts is to employ atomically defined and periodic supports (Coperet, C. et al., Angew. Chem. Int. Ed. 2003, 42, 156; Stalzer, M. M. et al., Catal. Lett. 2015, 145, 3). It is desired to utilize a chemically and thermally robust metal-organic framework (MOF) in lieu of a traditional metal oxide or activated carbon as a platform for supporting homogeneous complexes. MOFs are three-dimensional, crystalline, porous materials composed of inorganic nodes (metal ions or clusters) and organic linkers, and have been investigated for many applications (Furukawa, H. et al., Science 2013, 341, 1230444). Given the periodic structure of MOFs and the potential to determine the precise position of atoms using single X-ray diffraction studies, they are considered to be promising and underutilized catalytic supports.
One class of MOFs that has gained recognition for their exceptional stability is Zr- and Hf-based MOFs, which consist of Zr6 or Hf6 nodes [M6(μ3—O)4(μ3—OH)4(OH)4(H2O)4, M=Zr, Hf] and the tetra-carboxylate linker 1,3,6,8-tetrakis(p-benzoate)pyrene (H4TBAPy) (Cavka, J. H. et al., J. Am. Chem. Soc. 2008, 130, 13850; Feng, D. et al., Angew. Chem. Int. Ed. 2012, 51, 10307; Morris, W. et al., Inorg. Chem. 2012, 51, 6443; Furukawa, H. et al., J. Am. Chem. Soc. 2014, 136, 4369; Mondloch, J. E. et al., J. Am. Chem. Soc. 2013, 135, 10294; Beyzavi, M. H. et al., J. Am. Chem. Soc. 2014, 136, 15861). These MOFs exhibit large 29-30 Å hexagonal mesopores to facilitate mass transport (of both catalyst precursors and reactants/products) throughout the material, and accessible grafting sites in the form of —OH and —OH2 groups, the topology of which has been experimentally and computationally determined (Planas, N. et al., J. Phys. Chem. Lett. 2014, 5, 3716). It has been shown that these anchoring sites can be functionalized via atomic layer deposition (ALD), wet impregnation with organometallic precursors, and with carboxylate groups via ligand attachment (Yang, D. et al., J. Am. Chem. Soc. 2015; Deria, P. et al., J. Am. Chem. Soc. 2013, 135, 16801; Deria, P. et al., Chem. Commun. 2014, 50, 1965.
Incorporation of metal complexes into MOFs has been explored using three methodologies: (1) inclusion of metal complexes into MOF pores; (2) covalent attachment onto organic linkers; and (3) covalent attachment to functional groups associated with the inorganic nodes (Meilikhov, M. et al., Angew. Chem. Int. Ed. 2010, 49, 6212; Kalidindi, S. B. et al., Chem. Commun. 2011, 47, 8506; Zhang, Z. et al., J. Am. Chem. Soc. 2011, 134, 928; Li, B. et al., J. Am. Chem. Soc. 2014, 136, 1202; Lee, J. et al., Chem. Soc. Rev. 2009, 38, 1450; Yoon, M. et al., Chem. Rev. 2011, 112, 1196; Meilikhov, M. et al., J. Am. Chem. Soc. 2009, 131, 9644; Larabi, C. et al., Eur. J. Inorg. Chem. 2012, 2012, 3014; Nguyen, H. G. T. et al., ACS Catalysis 2014, 4, 2496. Compared to inclusion complexes, covalent attachment is more likely to lead to catalytic materials broadly useful for demanding heterogeneous reactions. It is believed that attachment to the node is more likely to lead to well-defined and periodic heterogeneous species given that installing appropriate grafting sites on linkers in a regular and controlled manner is often difficult.
Full characterization and preliminary olefin polymerization activity of an organozirconium precursor covalently attached to a Hf-based MOF (Scheme 1) has previously been reported (Bassett, J. M. et al., Acc. Chem. Res. 2010, 43, 323). Supported group 4 metal-alkyl species have been extensively investigated for nearly four decades due to their importance in olefin polymerization, hydrogenation, and other catalytic reactions (Ballard, D. G. H. Adv. Catal. 1973, 23, 263.; Yermakov, Y. et al., Adv. Catal. 1975, 24, 173; Williams, L. A. et al., Proc. Natl. Acad. Sci. U.S.A. 2013, 110, 413; Gu, W. et al., J. Am. Chem. Soc. 2015, 137, 6770).

It is therefore desirable to provide for the synthesis, full characterization, and preliminary olefin polymerization activity of an organozirconium precursor covalently attached to a group 4 metal-based, e.g. hafnium, metal-organic framework.